The math of comebacks
The point is this: Most of those games that are going really bad won't result in a comeback. You are better off only losing 10 minutes on those games (if we were allowed to surrender at 10) and saving 20-30 minutes trying to to comeback and using all of that time to play other ranked matches where you have a chance. The one out of 10 games where a comeback happens costs me 200 to 300 more minutes...trying in vain to pull a team together or overcome too many feeders. That time is better spent in situations where you have a chance, and saves much aggravation.
The fact that comebacks are possible is largely irrelevant.